The International Space Station (ISS)

Astronauts Thomas D. Jones and Mark L. Polansky, STS-98 mission specialists, are photographed during their sleep shift in the Destiny laboratory on the International Space Station (ISS).

Smith Johnston

Lauren Leveton

Alexandra Whitmire

Light stimulation can be used to help astronauts adjust their circadian rhythms. Smith L. Johnston, MD (right), explains the benefits of light stimulation to astronaut Michael E. Lopez-Alegria.


Kelsey Butler, Lauren Leveton, Alexandra Whitmire, Stéphane Dumonceau, Smith Johnston & colleague


PSiO for astronauts ?

Meeting in Houston, with NASA flight surgeon Smith Johnston and colleagues Alexandra Whitmire and Lauren Leveton

Stéphane Dumonceau presented the PSiO as an easy way to produce the famous 470 nanometers (blue light) wavelength and 625 nanometers (red light) wavelength to help astronauts stimulate retina light receptors.

S. Dumonceau : beside the deep relaxation MP3 COLOR sessions we have in red, we propose short meditation sessions with blue light + a dozen of turbo-nap programs in music. And we have several kinds of music : new age, latin jazz, lounge, rock !

S. Johnston : I think the PSiO is cool and fun to use. This is one of the great advantages of this technology ! Astronauts have several light stimulation tools but they sometimes don't use them.

S. Dumonceau : we can also customize the jet lag regulation sessions with the favorite music of each astronaut !

S. Johnston : at NASA, we consider each astronaut separately. Customized programs are really what we are looking for. For now, we wish that you get in touch with our sleep expert Steven Lockley, Professor at the Harvard University for a possible validation study.

See more about Steven Lockley :

Now we need more scientific data. Please provide us all the datas and research you have done.

S. Dumonceau : among the several EEG study which we conducted to assess the alpha relaxation effect of the PSiO technology, please see the latest study we have carried out to analyze the melatonin inhibition generated by the PSiO :

The partakers of the meeting

Stéphane Dumonceau is the designer of the PSiO technology. Expert in relaxation techniques and studying light stimulations since 1987 at the University of Brussels in the context of a PhD in Sports Psychology. See more at :

Smith Johnston : flight surgeon for NASA Space Center over the past 17 years, S. Johnston says, “It's my job to ensure that individuals sent into space are healthy. In terms of sleep, it is my responsibility to use everything in our armamentarium to make sure that astronauts can sleep and shift while in orbit.” - See more at:

S. Johnston : Blue light stimulates the human brain best because people evolved to respond to the color of Earth's sky, experts say. When astronauts' eyes are exposed to blue light, his or her body suppresses melatonin, known to be a sleep-inducing hormone. Blue also promotes the formation of melanopsin, a "protein pigment" that keeps people awake. In simple terms, the color red reverses the process. Melatonin increases, making astronauts sleepy, while melanopsin is suppressed. "You can dial in a natural day-night cycle on the space station" with the new light arrays,which are being developed by Boeing, Johnston said. It should work well, he added, unless astronauts look out the window at bedtime. They then run the risk of confusing their body clocks by exposing their eyes to natural sunlight reflecting off of the Earth.

Technology can go only so far in solving sleep problems, Johnston said. This is why NASA prescribes good "sleep hygiene" for its crews before and during space flight. Medications are used only as a last resort, and are tested extensively on Earth by each crew member. In case of emergency, astronauts must awaken easily even during the deepest stages of sleep. The astronauts also get practice sleeping under difficult circumstances by virtue of their demanding preflight schedules, which include flights to Russia and Japan for training. NASA works with the astronauts to minimize jet lag. Techniques that help for each crew member, such as wearing sunglasses on the plane and taking medications at a certain time, can then be used in orbit. Groups on Earth will benefit from the research, too, especially shift workers or travelers fighting jet lag, Johnston said.